LSD's that might be available are the TRD/Kazuma clutch-type 3-pinion LSD, the OEM 4-pinion Tundra TRD LSD, and the Detroit Trutrac.
Lockers that might still be made are the Powertrax "Lock-right," "No-Slip," ARB Air Locker, Detroit Softlocker, Harrop, Nitro "Lunch Box"
They have to be designed for 8" 2pinion it uses a larger diameter mounting bolt pattern and because more space inside the housing necessary to accommodate the large bearing cap. The different bolt pattern also makes it very impractical to swap in an electric locking Toyota diff (the whole mounting flange would have to be re-done using a special jig).
- Carrier bearing truss and newer housing adds significant strength over V6 and 4cyl diffs 8"
- Uses V6 carrier bearings, larger pinion bearings
- Uses shims for backlash adjustment instead of threaded adjusters
- Twelve 12mm Ring gear bolts
- 10mm axle housing studs with 14mm nuts
- 30 splilne axles
- 30 spline pinion
Note T100 diffs are somewhat unique This is good link that has info on T100 diffs
http://home.4x4wire.com/erik/diffs/
Good Luck.